A wealthy woman named Hisako Osada is found murdered in a briefcase that was delivered to her home. Whilst the police suspect Hisako's lover to be the culprit, her daughter, An, believes someone else is behind the murder and calls on Shinjūrō to investigate. Their investigation leads them to look into an idol group Hisako managed named Yonagahime 3+1, one of its members of which, Eri, was allegedly killed in a terrorist attack. Inga uses her powers on one of Yonagahime's members, who reveals that Eri never existed and was just used by Hisako to skyrocket the band's popularity during a war.

Rie calls on Shinjūrō and Inga to accept a request from Mitsuko Sasa, whose adopted brother Kazamori caught on fire and died, allegedly related to a curse from her father, Komamori, who died in a similar manner seven years ago. As Izumi's group conducts their own investigations on the cause of Kazamori's death, Inga uses her powers to reveal that Kazamori is actually a supercomputer.